The quality of surfaces is a significant property of objects used in everyday life such as motor vehicles or other consumer items, thus decisively determining their overall impression on a human observer. Examples therefor are high-gloss or metallic finishes of car bodies.
The reproducible evaluation of the quality of surfaces in particular of said high-gloss finishes requires measuring instruments which capture precisely those physical quantities which decisively determine the overall impression on a human observer. Various methods and devices are known in the prior art for determining the visual properties and specifically the reflection and diffusion characteristics of surfaces.
There is the problem that the optical impression of surfaces on a human observer also depends on the resolution capability of the human eye which in turn depends on the distance of the observer from the object, for example a vehicle.
At short distances, the human eye is capable of precisely resolving for example different color contrasts. At longer distances for instance periodic patterns will be better recognizable. The visibility of e.g. periodic textures to the human eye depends on the wavelength or frequency of the texture and on the distance of the eye from the observed object.